Fuel Management

[N941WR]

I was wondering how others manage their fuel tanks, how often do you switch tanks?

I do it every 30 minutes to help keep the plane balanced. The Dynon is helpful in reminding me to do this.

Update:
Sorry guys, I did not include an "other" options. At least I didn't make that clear. If you do something different, select option 4.

[kentb]

If I am going very far (need max endurance) I use my fuel flow (fuel used) on my engine monitor. It is more accurate then my fuel level gauges, never off more then 1 gal on any fill-up.
I switch tanks every 2 gal. used. When I am using tank one between 4 and 2 gal. tank two still has 4 gal. in it. When I make the switch to tank two (tank on reaches 2 gal.) I am looking for a place to find more fuel.

Kent

[dan]

When leading a formation flight, I issue a "Sharpie Flight OPS CHECK" every 30 minutes. The 496's timer cues me on that one.

But as far as switching tanks goes, I burn off fuel to keep the aileron trim centered. Any time you've got aileron trim in, that's DRAG. Trim is deflecting controls to resolve an imbalance. If you want peak speed and/or economy, you gotta keep those control surfaces IN TRAIL.

When I have the TruTrak autopilot engaged, it's a great indicator of when to switch tanks. When everything is in trim, you don't see the stick move. But if there's a fuel imbalance (heavy wing) you can see the stick "pulsating" every few seconds. I disable the autopilot to confirm a wing is heavy, and then I switch tanks. It typically works out to 30-40 minutes at 7 gph.

On really long legs, where I want to maximize my range, I need to keep an exact tally of how much fuel I have in each tank (because I don't trust my quantity indications). I burn from the heavy side first, and I start a written table in my little notepad. It starts out like:

L R Total
21.0 (21.0) 42.0

and I circle whichever side I'm burning from (i.e. above, I'm burning off the right).

So let's say 30 minutes later I have a heavy wing and switch tanks. Then again, and again. After a while, the table looks like this:

L R Total
21.0 (21.0) 42.0
(21.0) 17.5 38.5
16.8 (17.5) 34.3
(16.8) 13.1 29.9
13.3 (13.1) 26.2
etc.

At the end of a 4:45 leg, I have a pretty darn near exact idea of how much fuel is left in each tank.

Anyway, that's my technique for long trips. It's also a GREAT hypoxia indicator. If I have any trouble doing simple math, I turn the O2 up. I also use a pulse oximeter, but that's another thread...

[Mel]

You didn't include my option. I switch every 5 gallons.

[pierre smith]

Originally Posted by dan

When leading a formation flight, I issue a "Sharpie Flight OPS CHECK" every 30 minutes. The 496's timer cues me on that one.

...

Dan,
Can you tell me how to set the timer in the 496? I'm too busy to read the manual just now.

Thanks,

Pierre

[Geico266]

At 7.5 GPH every 60 mins works for me.

[n2prise]

I use my Grand Rapids EIS-4000 engine monitor timer every thirty minutes. At my typical cruising speed in the RV-9A, that amounts to 3 gallons per side at 160 MPH true airspeed. I continually watch fuel burn and EGTs to balance the mixture to the cylinders, etc. During the trip to keep me active, I don't just drone along on autopilot. I also use the GPS 296 "nearest" button to select WX stations along the route for altimeter settings, and ARTCC frequencies. When I am in solid VFR conditions, I listen to those guys when I don't need to use their services. Why give them more work to do when things are fine? If I hear them mention unverified traffic at my location to another pilot, I know to be more vigilant and sometimes will speak up and accept flight following. When I get to busier areas like the Florida East coast, I always use flight following to stay clear of other air traffic.

Jerry K. Thorne
East Ridge, TN
RV-9A - - N2PZ

[dan]

Originally Posted by pierre smith

Can you tell me how to set the timer in the 496? I'm too busy to read the manual just now.

Garmin Customer Support, how may I help you?

No, but seriously, I think it's in the SETUP menu. Timers iirc. RTFM or just play with it.